What should I put on the visa number and departure flight details when filling out the TM6 form in Thailand?

The TM6 form for re-entry into Thailand can be filled out as follows: 1. If you're on a NON-O extension, it is generally suggested to leave the visa number blank, though one individual reported using the number on their extension. 2. Departure flight details can also be left blank as the individual resides in Thailand.